Former Rep. Tom Perriello, a Democratic candidate for Governor of Virginia, said on the campaign trail that the 2016 election was a “political and constitutional September 11,” Free Beacon reports.

“The election of Donald Trump was a little bit like, you know, a political and constitutional September 11 for us, if I can be honest,” Perriello said in Afton, Virginia.

As congressman, Perriello was unseated after just one term. He later took to Twitter to apologize for his remarks.

“I regret the comparison and apologize,” Perriello said. “Won’t do it again.”

Perriello is a favorite of liberal Democrats like former President Barack Obama, and characterizes himself as a more “progressive” option than current Lieutenant Governor Ralph Northam, his Democratic opponent.